Waldman doubts it will pay major dividends:
If that serious challenger to Clinton does emerge, he or she is going to need to do a whole lot more than run to the former secretary of state’s left, because in presidential politics, ideological crusades almost always fail. In the last half-century, spanning 13 presidential elections and 26 nominees, there are only three candidates one could plausibly argue became a party’s nominee by being the most ideologically true candidate. All three—Barry Goldwater in 1964, George McGovern in 1972 and Ronald Reagan in 1980—ran superlative primary campaigns. And none had to overcome a candidate with the strength Clinton would have in 2016.
In a later post, he expands his argument:
As they approach the end of the Obama years, Democrats are going to have to hash out who they are, what they believe, and where they want to go. But the reason being the most liberal candidate is insufficient is that primary voters aren’t ideological maximizers, they’re ideological satisficers.
Satisficing is a term originated in the 1950s by economist Herbert Simon, who argued that the classical understanding of economic actors seeking to maximize utility not only didn’t make much sense (because obtaining all relevant information to reach that maximal point can involve huge costs), but didn’t reflect the way people and firms acted in the real world. Instead of making the best choice, people often search for something that is good enough. After some threshold of acceptability is reached, they stop their search. If there’s a reasonably good taqueria down the block, you’re not going to spend weeks searching for the best burrito in the state; you’ll just get your burritos there. And subsequent research suggests you’ll be happier for it.
The Dish 